A major aim of this research is to delineate the pathway of carnitine biosynthesis in Neurospora crassa and the rat to demonstrate each postulated transformation in purified enzyme systems. Work will continue on the manner in which epsilon-N-trimethyllysine is converted to gamma-butyrobetaine in the rat. Metabolites of lysine have been found associated with lipid fractions in rat liver and one of these (X) appears to also derive from trimethyllysine. The chemical nature of (X) will be investigated and should lead to details of carnitine biogenesis which may be occurring at the lipid level. Such findings would influence our present attempts to demonstrate SAM:lysine-epsilon-N -methyltransferase in rat liver systems. This latter enzyme has been purified to homogeneity in Neurospora crassa and studies of its chemical and enzymatic properties (especially kinetics) will continue. Attempts to find nutritional conditions (e.g., diets limiting in carnitine and its amino acid percursors, lysine and methionine) which will lead to a carnitine deficiency in the rat will continue; success would provide an animal model for appropriate physiological, biochemical and pathological studies of carnitine metabolism. Our finding that the muscle carnitine level in Becker and Duchenne dystrophy is significantly lower than a series of muscle biopsy samples from normal and other neuromuscular diseased patients will be followed up by appropriate in vitro studies of carnitine metabolism in normal vs. pathological muscle cells grown in tissue culture (Dr. R. Roelofs, Neurology Department, Vanderbilt University School of Medicine).